clear all;
close all;
clc;

%n = -20:20;
%x = 0.8.^abs(n);
n = 0:10
x = n>=0;
w = linspace(-pi, pi, 500);
X = x * exp(-1j*n'*w);
subplot(3,1,1); stem(n, x, 'fill');
subplot(3,1,2); plot(w, abs(X));
subplot(3,1,3); plot(w, angle(X));
